DESC:FIELD OF THE INVENTION
The present invention relates generally to ophthalmic instruments, particularly to light delivery system. More particularly, the present invention relates to customized red light delivery system through ophthalmic operating microscope for photo dynamic therapy (PDT).

BACKGROUND ART
Around the world, retinal and choroidal neovascularization are a major cause of significant visual impairment. When the retinal layers are damaged by diseases like macular degeneration, the choroid may produce new blood vessels which grow up through the damaged layers and leak or bleed into the retina. Once this happens, the vision can become blurry, darkened or distorted. Choroidal neovascularization is a major cause of central visual loss. New vessels in the eye are also produced by simple aging process or by long standing diseases like diabetes and as a result of complications of high blood pressure or other systemic diseases. These can be sight threatening and often lead to blindness.

Existing treatments include laser photocoagulation, injections of anti VEGF drugs into the eye and photo dynamic therapy (PDT) using a photosensitive dye Verteporfin and an expensive red laser which excites the dye. The laser used to interact with the dye in PDT is itself very costly and has several disadvantages like causing a tear in the choroid (choroidal rip) or even lead to haemorrhage which itself can lead to loss of vision. The problem is addressed by reducing the dose of the dye since the dye has been used several times and later by reducing the power of the laser and even reducing the laser exposure time. Still problems persist, in addition to the enormous cost of the laser itself.

There exists another method, where a non-laser red light using a fluorescent bulb gave results close to the results obtained by the accepted PDT protocol but however, there were issues in light delivery.

US7320786 discloses methods, kits, and instructions to treat neovasculature diseases of the eye through the administration of a targeted photosensitizing agent and subsequent exposure to light of specific wavelength sufficient to photo activate photosensitizing agent. However, in this, the light source is collimated and focussed and also the spot size depends on lesion. Further it has extremly long cumulative exposure times and the light is delivered through various routes.

US6319273 discloses a photodynamic therapy (PDT) device utilizing a non-coherent light source to activate a photo reactive agent for treating a diseased site in a patient's eye. In one embodiment the light sources are blue and red light emitting diodes (LEDs).

US9226917 discloses use of a combination of photodynamic therapy and an anti-VEGF agent in the treatment of conditions characterized by unwanted choroidal neovasculature. However, the cited document is generalised and non specific whereas in the present invention the light source is specific in power and duration.

US9192780 is directed towards photo modulation and/or photo rejuvenation of retinal epithelial cells, to treat a variety of vision disorders.
US8888765 discloses infrared binocular indirect ophthalmoscope (iBIO) with a delivery device for the simultaneous examination and treatment of the human eye.

Accordingly, there exists a need for customized non-laser light source of specific wavelength which prevents heat related changes in the area under treatment.

OBJECTS OF THE INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the system of the present invention.

It is the primary object of the present invention to provide a light delivery system for the treatment of retinal and choroidal new vessels.

It is another object of the present invention to provide a customized red light delivery system through ophthalmic operating microscope for photo dynamic therapy (PDT).

It is another object of the present invention, wherein the customization depends on size, location and number of new vessels.

It is another object of the present invention, wherein the red light is customized to expose on open eye through transpupillary approach under controlled environment setting and the red light need not focus on the retina.

It is another object of the present invention, wherein 60% of the red light is exposed on the open eye for a predefined time.

It is another object of the present invention, wherein diameter of the red light at the focal point of the ophthalmic operating microscope is maintained at marginally bigger than the average corneal diameter.

It is another object of the present invention, wherein the red light of specific wavelength when exposed to the Verteporfin dye reacts with the dye and releases nascent oxygen molecules which produce a thrombus within the affected new vessels.

It is another object of the present invention, wherein the red light of specific wavelength when exposed to the Verteporfin dye, fills the eye with red light and allows the lesion and dye to find the light.

It is another object of the present invention, wherein the customized red light delivery system uses cold light source and hence does not produce heat related changes in the area under treatment.

It is another object of the present invention, wherein the customized red light delivery system causes photo occlusion of new vessels.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention, there is provided a customized red light delivery system through ophthalmic operating microscope for photo dynamic therapy, the system comprising:
bino assembly;
rotatable arm assembly; and
control panel,
wherein the control panel includes time adjusting feature and illumination feature to control duration of exposure of light and power to be used,
wherein the bino assembly includes red light emitting diode (LED); eyepiece; fine focussing knob; and Interpupillary distance (IPD) adjusting knob,
wherein the customization of the red light delivery depends on size, location and number of new vessels,
wherein the red light is customized to expose on open eye through transpupillary approach under controlled environment setting and need not focus on the retina,
wherein the customized red light delivery system causes photo occlusion of new vessels, and
wherein the system uses cold light source and therefore does not produces heat related changes in the area under treatment.

It is another aspect of the present invention, wherein red light is of wavelength 685nm ± 1.

It is another aspect of the present invention, wherein only 60% of the red light is exposed on the open eye for a predefined time.

It is another aspect of the present invention, wherein when the red light when exposed to Verteporfin dye reacts with the dye and releases nascent oxygen molecules which produce a thrombus within the affected new vessels.

It is another aspect of the present invention, wherein the Verteporfin dye fills the eye with red light and allows the lesion and dye to find the light and hence spot size does not depends on lesion.

It is another aspect of the present invention, wherein the control panel has control to automatically shut off the power.

It is another aspect of the present invention, wherein the control panel is mounted on a pillar assembly and is connected to the bino assembly through the rotatable arm assembly.

It is another aspect of the present invention, wherein the system includes switch assembly to control the movement of the system.

BRIEF DESCRIPTION OF THE DRAWING
Figure 1: illustrates a customized red light delivery system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURE
The present invention as herein described relates to a customized red light delivery system through ophthalmic operating microscope for photo dynamic therapy (PDT). Referring to Figure 1, the customized red light delivery system comprising of bino assembly [1]; rotatable arm assembly [2]; and control panel [3] to control the duration of exposure of light and the power to be used. Said components are connected together and are assembled on a pillar assembly [4]. The system further includes a switch assembly [6] to control the movement of the system, said switch assembly [6] in one aspect is operable by foot. The control panel [3] is mounted on the pillar assembly [4] and is connected to the bino assembly [1] through the rotatable arm assembly [2]. The pillar assembly [4] includes a base assembly [5] which may optionally include wheels. The control panel [3] includes time adjusting feature [3a] and illumination feature [3b]. The control panel [3] has control to automatically shut off the power. The bino assembly [1] includes IntelliWhite (iW) light emitting diode (LED) [1a]; eyepiece [1b]; fine focussing knob [1c]; and Interpupillary distance (IPD) adjusting knob [1d]. The arm assembly [2] has 360 degree rotating arm lock knob [2a] to rotate as per requirement. The illumination feature [3b] provides 0 to 99% illumination.

The customization depends on size, location and number of new vessels. Non-laser red light [1a] of wavelength 685nm ± 1 is customized to expose on the open eye through transpupillary approach under controlled environment setting and the red light [1a] need not focus on the retina. The diameter of the red light [1a] at the focal point of the ophthalmic operating microscope is maintained at marginally bigger than the average corneal diameter. Only 60% of 450 mw of the red light [1a] is exposed on the open eye for a predefined time. When the red light [1a] of specific wavelength when exposed to the Verteporfin dye reacts with the dye and releases nascent oxygen molecules which produce a thrombus within the affected new vessels. Here, the spot size does not depends on lesion. The Verteporfin dye fills the eye with red light [1a] and allows the lesion and dye to find the light. The customized red light delivery system causes photo occlusion of new vessels and the system uses a cold light source and therefore does not produces heat related changes in the area under treatment.

Procedure:
For illustration:
Approximately 7ml of distilled water is injected into Verteporfin dye vial. Shake well so that no precipitates are seen. Approximately 3ml of the dye solution is mixed with about 27ml of 5% dextrose. Said 30ml solution is injected to a patient over about 10 minutes and allowed to wait for about 15 minutes. The patient is then positioned and exposed to 60% of 450 mw of the red light for about 2-4 minutes, and then shift the patient to a room with low light. Repeat about 2-4 minutes exposure of red light after 2 hours. The result achieved using the proposed system is shown below.

Results:

The advantages of the present invention are as follows:
Cost effective customized red light delivery system thereby eliminating the need for a laser or a powerful light.
No contact lens, no speculum, no topical.
No side effects and no occurrence of choroidal tear or bleed.
The red light is customized to expose on the open eye and does not have to be exactly focused on the new vessel.
,CLAIMS:WE CLAIM:

1. A customized red light delivery system through ophthalmic operating microscope for photo dynamic therapy, the system comprising:
bino assembly [1];
rotatable arm assembly [2]; and
control panel [3],
wherein the control panel [3] includes time adjusting feature [3a] and illumination feature
[3b] to control duration of exposure of light and power to be used,
wherein the bino assembly [1] includes red light emitting diode (LED) [1a]; eyepiece [1b]; fine focussing knob [1c]; and Interpupillary distance (IPD) adjusting knob [1d],
wherein the customization of the red light delivery depends on size, location and number of new vessels,
wherein the red light [1a] is customized to expose on open eye through transpupillary approach under controlled environment setting and need not focus on the retina,
wherein the customized red light delivery system causes photo occlusion of new vessels, and
wherein the system uses cold light source [1a] and therefore does not produces heat related changes in the area under treatment.

2. The system as claimed in claim 1, wherein red light [1a] is of wavelength 685nm ± 1.

3. The system as claimed in claim 2, wherein only 60% of the red light [1a] is exposed on the open eye for a predefined time.
4. The system as claimed in claim 3, wherein when the red light [1a] when exposed to Verteporfin dye reacts with the dye and releases nascent oxygen molecules which produce a thrombus within the affected new vessels.

5. The system as claimed in claim 4, wherein the Verteporfin dye fills the eye with red light [1a] and allows the lesion and dye to find the light and hence spot size does not depends on lesion.

6. The system as claimed in claim 1, wherein the control panel [3] has control to automatically shut off the power.

7. The system as claimed in claim 6, wherein the control panel [3] is mounted on a pillar assembly [4] and is connected to the bino assembly [1] through the rotatable arm assembly [2].

8. The system as claimed in claim 1 includes switch assembly [6] to control the movement of the system.